<template>
    <div class="goods-sku">
        <dl v-for="item in goods.specs" :key="item.id">
            <dt>{{ item.name }}</dt>
            <dd>
                <template v-for="val in item.values" :key="val.name">
                    <img
                        :class="{
                            selected: val.selected,
                            disabled: val.disabled,
                        }"
                        @click="clickSpecs(item, val)"
                        v-if="val.picture"
                        :src="val.picture"
                    />
                    <span
                        :class="{
                            selected: val.selected,
                            disabled: val.disabled,
                        }"
                        @click="clickSpecs(item, val)"
                        v-else
                        >{{ val.name }}</span
                    >
                </template>
            </dd>
        </dl>
    </div>
</template>
<script>
import { watchEffect } from "vue";
import getPowerSet from "./power-set";

const spliter = "★";
// 根据skus数据得到路径字典对象
const getPathMap = (skus) => {
    const pathMap = {};
    if (skus && skus.length > 0) {
        skus.forEach((sku) => {
            // 1. 过滤出有库存有效的sku
            if (sku.inventory) {
                // 2. 得到sku属性值数组
                const specs = sku.specs.map((spec) => spec.valueName);
                // 3. 得到sku属性值数组的子集
                const powerSet = getPowerSet(specs);
                // 4. 设置给路径字典对象
                powerSet.forEach((set) => {
                    const key = set.join(spliter);
                    // 如果没有就先初始化一个空数组
                    if (!pathMap[key]) {
                        pathMap[key] = [];
                    }
                    pathMap[key].push(sku.id);
                });
            }
        });
    }
    return pathMap;
};

// 初始化禁用状态
function initDisabledStatus(specs, pathMap) {
    if (specs && specs.length > 0) {
        specs.forEach((spec) => {
            spec.values.forEach((val) => {
                // 设置禁用状态
                val.disabled = !pathMap[val.name];
            });
        });
    }
}

// 得到当前选中规格集合
const getSelectedArr = (specs) => {
    const selectedArr = [];
    specs.forEach((spec, index) => {
        const selectedVal = spec.values.find((val) => val.selected);
        if (selectedVal) {
            selectedArr[index] = selectedVal.name;
        } else {
            selectedArr[index] = undefined;
        }
    });
    return selectedArr;
};

// 更新按钮的禁用状态
const updateDisabledStatus = (specs, pathMap) => {
    // 遍历每一种规格
    specs.forEach((item, i) => {
        // 拿到当前选择的项目
        const selectedArr = getSelectedArr(specs);
        // 遍历每一个按钮
        item.values.forEach((val) => {
            if (!val.selected) {
                selectedArr[i] = val.name;
                // 去掉undefined之后组合成key
                const key = selectedArr.filter((value) => value).join(spliter);
                val.disabled = !pathMap[key];
            }
        });
    });
};

export default {
    name: "XtxGoodSku",
    props: {
        // specs:所有的规格信息  skus:所有的sku组合
        goods: {
            type: Object,
            default: () => ({ specs: [], skus: [] }),
        },
    },
    emits: ["change"],
    setup(props, { emit }) {
        let pathMap = {};
        watchEffect(() => {
            // 得到所有字典集合
            pathMap = getPathMap(props.goods.skus);
            // 组件初始化的时候更新禁用状态
            initDisabledStatus(props.goods.specs, pathMap);
        });

        const clickSpecs = (item, val) => {
            if (val.disabled) return false;
            // 选中与取消选中逻辑
            if (val.selected) {
                val.selected = false;
            } else {
                item.values.forEach((bv) => {
                    bv.selected = false;
                });
                val.selected = true;
            }
            // 点击之后再次更新选中状态
            updateDisabledStatus(props.goods.specs, pathMap);
            // 把选择的sku信息传出去给父组件
            // 触发change事件将sku数据传递出去
            const selectedArr = getSelectedArr(props.goods.specs).filter(
                (value) => value
            );
            // 如果选中得规格数量和传入得规格总数相等则传出完整信息(都选择了)
            // 否则传出空对象
            if (selectedArr.length === props.goods.specs.length) {
                // 从路径字典中得到skuId
                const skuId = pathMap[selectedArr.join(spliter)][0];
                const sku = props.goods.skus.find((sku) => sku.id === skuId);
                // 传递数据给父组件
                emit("change", {
                    skuId: sku.id,
                    price: sku.price,
                    oldPrice: sku.oldPrice,
                    inventory: sku.inventory,
                    specsText: sku.specs
                        .reduce((p, n) => `${p} ${n.name}：${n.valueName}`, "")
                        .trim(),
                });
            } else {
                emit("change", {});
            }
        };
        return { clickSpecs };
    },
};
</script>

<style scoped lang="scss">
@mixin sku-state-mixin {
    border: 1px solid #e4e4e4;
    margin-right: 10px;
    cursor: pointer;

    &.selected {
        border-color: $xtxColor;
    }

    &.disabled {
        opacity: 0.6;
        border-style: dashed;
        cursor: not-allowed;
    }
}

.goods-sku {
    padding-left: 10px;
    padding-top: 20px;

    dl {
        display: flex;
        padding-bottom: 20px;
        align-items: center;

        dt {
            width: 50px;
            color: #999;
        }

        dd {
            flex: 1;
            color: #666;

            > img {
                width: 50px;
                height: 50px;
                margin-bottom: 4px;
                @include sku-state-mixin;
            }

            > span {
                display: inline-block;
                height: 30px;
                line-height: 28px;
                padding: 0 20px;
                margin-bottom: 4px;
                @include sku-state-mixin;
            }
        }
    }
}
</style>
